On June 14, 1775, the Second Continental Congress in Philadelphia voted to "adopt" troops in Boston and New York City, forming the force that, in the centuries since, grew to become the US Army.

From it start as state militias joined together to fight the fearsomeBritish redcoats, the US Army has gone on to become the strongest fighting force in the world.

The USArmy, the largest branch of the US armed forces, is charged with land-based operations, drawing on some of thebest technology in the world to do it.

Here are some images from the US Army's storied history.

Some of the first pictures of the US Army are of Union soldiers during the Civil War. Here's a photo of soldiers camping along the west bank of the Rappahonnock River at Fredericksburg, Virginia, during the Battle of Chancellorsville.

One of the most famous Army units was Teddy Roosevelt's "Rough Riders." They are pictured here after the Battle of San Juan in 1898.

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Library of Congress

The Army began acquiring fixed-wing aircraft in 1910. Here, Army planes fly over Manhattan in 1939.

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New York Public Library Digital Archives

World War I was marked by horrors like poison gas and fighting in trenches, the latter of which often were plagued by rats and lice and were breeding grounds for disease. The US sent thousands of "doughboys" to fight in France, like those shown here charging over the top of a trench in 1917.

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(AP Photo)

US soldiers in France in 1918 wearing gas masks.

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Otis Historical Archives National Museum of Health and Medicine

On November 11, 1918, the Armistice of Compigne was signed between the Allies and Germany, effectively ending World War I. Here, soldiers celebrate the war's end.

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US Army

The US Army troops were the bulk of the American force that came ashore during the D-Day invasion on June 6, 1944.

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US Army Photo

The 442nd Regimental Combat Team, composed almost entirely of American soldiers of Japanese descent who volunteered to fight, won acclaim for its bravery during World War II. It is the most decorated force in US Army history.

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Army Center for Military History

The Army also fought alongside the Marines in the Pacific against Japan. Here, infantrymen advance alongside an M4 Sherman tank in the Solomon Islands.

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US Army

President Harry Truman desegregated the Army in 1948. The Korean War was the first major conflict to have integrated units.

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James Cox/US Army

The Army has few fixed-wing aircraft, but it operates many kinds of rotary-wing aircraft. Here, US Army helicopters drop off American soldiers during an offensive against the Viet Cong during the Vietnam War.

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Horst Faas/AP

Here, as fellow troopers aid wounded comrades, the first sergeant of A Company, 101st Airborne Division, guides a medevac helicopter through the jungle foliage to pick up casualties suffered during a five-day patrol near Hue in Vietnam in April 1968.

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AP

The Army had a central role in Operation Desert Storm, the US-led mission to liberate Kuwait from Iraq in 1990-1991. Here, troops from the Army's 7th Corps huddle with protective gear, fearing a chemical-weapons strike by Saddam Hussein after the US started bombing Iraq.

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Peter Dejong/AP

US Army self-propelled 155mm Howitzers assigned to the 7th Corps head toward the Kuwaiti border to force out Iraqi forces.

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Peter Dejong/AP

The Army has also functioned as a police force in war-torn areas. Two soldiers here provide security during a foot patrol in Ramadi, Iraq.

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Tech. Sgt. Jeremy T. Lock/US Air Force

Members of the Army National Guard help serve in peacekeeping missions around the world and aid US citizens during natural disasters. Here, a member of the Louisiana Army National Guard helps a child evacuate from flooding caused by Hurricane Isaac in 2012.

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U.S. Army / Megan Garcia

A Sikorsky UH-60 Black Hawk helicopter drops off a soldier. Black Hawks have been in service since 1979 and cost around $21.3 million.

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U.S. Army / Sgt. Trey Harvey

Soldiers practice repelling out of a Black Hawk helicopter at Fort Hood Air Assault School.

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U.S. Army / Sgt. Richard Wrigley

The Army also includes airborne divisions. Here, paratrooper Staff Sgt. Travis Surber, a paratrooper with the 173rd Brigade Combat Team's Battle Company of the 2nd Battalion, 503rd Infantry Regiment, parachutes out of a C-130 Hercules Transport Aircraft and into the Ukraine sky.

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US Army/Staff Sgt. Travis Surber

The US Army even has its own parachute team.

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Sgt. 1st Class Joe Abeln/US Army

The Army also has its own special-operations team, the Army Rangers, who trace their lineage back to colonial times.